Manage system users on your Amazon EC2 Linux instance - Amazon Elastic Compute Cloud
Default usernamesConsiderationsCreate a userRemove a user

Manage system users on your Amazon EC2 Linux instance

Each Linux instance launches with a default Linux system user. You can add users to your instance and delete users.

For the default user, the default username is determined by the AMI that was specified when you launched the instance.

Note

By default, password authentication and root login are disabled, and sudo is enabled. To log in to your instance, you must use a key pair. For more information about logging in, see Connect to your Linux instance using SSH.

You can allow password authentication and root login for your instance. For more information, see the documentation for your operating system.

Note

Linux system users should not be confused with IAM users. For more information, see IAM users in the IAM User Guide.

Default usernames

The default username for your EC2 instance is determined by the AMI that was specified when you launched the instance.

The default usernames are:

  • For an Amazon Linux AMI, the username is ec2-user.

  • For a CentOS AMI, the username is centos or ec2-user.

  • For a Debian AMI, the username is admin.

  • For a Fedora AMI, the username is fedora or ec2-user.

  • For a RHEL AMI, the username is ec2-user or root.

  • For a SUSE AMI, the username is ec2-user or root.

  • For an Ubuntu AMI, the username is ubuntu.

  • For an Oracle AMI, the username is ec2-user.

  • For a Bitnami AMI, the username is bitnami.

Note

To find the default username for other Linux distributions, check with the AMI provider.

Considerations

Using the default user is adequate for many applications. However, you may choose to add users so that individuals can have their own files and workspaces. Furthermore, creating users for new users is much more secure than granting multiple (possibly inexperienced) users access to the default user, because the default user can cause a lot of damage to a system when used improperly. For more information, see Tips for Securing Your EC2 Instance.

To enable users SSH access to your EC2 instance using a Linux system user, you must share the SSH key with the user. Alternatively, you can use EC2 Instance Connect to provide access to users without the need to share and manage SSH keys. For more information, see Connect to your Linux instance using EC2 Instance Connect.

Create a user

First create the user, and then add the SSH public key that allows the user to connect to and log into the instance.

Important

In Step 1 of this procedure, you create a new key pair. Because a key pair functions like a password, it's crucial to handle it securely. If you create a key pair for a user, you must ensure that the private key is sent to them securely. Alternatively, the user can complete Steps 1 and 2 by creating their own key pair, keeping the private key secure on their machine, and then sending you the public key to complete the procedure from Step 3.

To create a user

  1. Create a new key pair. You must provide the .pem file to the user for whom you are creating the user. They must use this file to connect to the instance.

  2. Retrieve the public key from the key pair that you created in the previous step.

    $ ssh-keygen -y -f /path_to_key_pair/key-pair-name.pem

    The command returns the public key, as shown in the following example.

    ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQClKsfkNkuSevGj3eYhCe53pcjqP3maAhDFcvBS7O6Vhz2ItxCih+PnDSUaw+WNQn/mZphTk/a/gU8jEzoOWbkM4yxyb/wB96xbiFveSFJuOp/d6RJhJOI0iBXrlsLnBItntckiJ7FbtxJMXLvvwJryDUilBMTjYtwB+QhYXUMOzce5Pjz5/i8SeJtjnV3iAoG/cQk+0FzZqaeJAAHco+CY/5WrUBkrHmFJr6HcXkvJdWPkYQS3xqC0+FmUZofz221CBt5IMucxXPkX4rWi+z7wB3RbBQoQzd8v7yeb7OzlPnWOyN0qFU0XA246RA8QFYiCNYwI3f05p6KLxEXAMPLE

  3. Connect to the instance.

  4. Use the adduser command to create the user and add it to the system (with an entry in the /etc/passwd file). The command also creates a group and a home directory for the user. In this example, the user is named newuser.

    • AL2023 and Amazon Linux 2

      With AL2023 and Amazon Linux 2, the user is created with password authentication disabled by default.

      [ec2-user ~]$ sudo adduser newuser

    • Ubuntu

      Include the --disabled-password parameter to create the user with password authentication disabled.

      [ubuntu ~]$ sudo adduser newuser --disabled-password

  5. Switch to the new user so that the directory and file that you create will have the proper ownership.

    [ec2-user ~]$ sudo su - newuser

    The prompt changes from ec2-user to newuser to indicate that you have switched the shell session to the new user.

  6. Add the SSH public key to the user. First create a directory in the user's home directory for the SSH key file, then create the key file, and finally paste the public key into the key file, as described in the following sub-steps.

    1. Create a .ssh directory in the newuser home directory and change its file permissions to 700 (only the owner can read, write, or open the directory).

      [newuser ~]$ mkdir .ssh
      [newuser ~]$ chmod 700 .ssh
      Important

      Without these exact file permissions, the user will not be able to log in.

    2. Create a file named authorized_keys in the .ssh directory and change its file permissions to 600 (only the owner can read or write to the file).

      [newuser ~]$ touch .ssh/authorized_keys
      [newuser ~]$ chmod 600 .ssh/authorized_keys
      Important

      Without these exact file permissions, the user will not be able to log in.

    3. Open the authorized_keys file using your favorite text editor (such as vim or nano).

      [newuser ~]$ nano .ssh/authorized_keys

      Paste the public key that you retrieved in Step 2 into the file and save the changes.

      Important

      Ensure that you paste the public key in one continuous line. The public key must not be split over multiple lines.

      The user should now be able to log into the newuser user on your instance, using the private key that corresponds to the public key that you added to the authorized_keys file. For more information about the different methods of connecting to a Linux instance, see Connect to your Linux instance using SSH.

Remove a user

If a user is no longer needed, you can remove that user so that it can no longer be used.

Use the userdel command to remove the user from the system. When you specify the -r parameter, the user's home directory and mail spool are deleted. To keep the user's home directory and mail spool, omit the -r parameter.

[ec2-user ~]$ sudo userdel -r olduser